1. Field of the Invention
The present general inventive concept relates to a liquid crystal display, and more particularly, to a liquid crystal display having a light emitting diode (LED) as a light source.
2. Description of the Related Art
Recently, flat panel displays, such as a liquid crystal display (LCD), a plasma display panel (PDP), or an organic light emitting diode (OLED), have been widely developed to replace a conventional cathode ray tube (CRT).
The LCD comprises a liquid crystal display panel, which has a thin film transistor substrate, a color filter substrate, and liquid crystal interposed between the thin film transistor substrate and the color filter substrate. Since the LCD is a non-light emitting apparatus, the LCD needs a backlight unit, which is disposed on a rear surface of the thin film transistor substrate, to supply light to the liquid crystal display panel. The amount of transmission of the light emitted from the backlight unit is controlled according to an array state of the liquid crystal. The LCD panel and the backlight unit are accommodated in a chassis.
The backlight unit can be classified as one of an edge type backlight and a direct type backlight according to a position of a light source. The edge type backlight has a structure in which the light source is disposed on a lateral part of a light guide plate. The edge type backlight is applied to a relatively small liquid crystal display, which is generally used in laptop and desktop computers. The edge type backlight is advantageous for having high uniformity of luminance, long lifetime, and thin thickness.
A light emitting diode (LED) has been widely used as the light source of the backlight unit due to its high brightness and excellent color realization. However, the LED generates much heat compared to other light sources, such as a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (EEFL). The heat from the LED may lower brightness and cause color shifts if it is not properly discharged.
Conventional backlight units use a radiating fin, a heat pipe, and a cooling fan to remove heat generated by the LED, thereby making the LCD heavier and thicker.